Syringe



May 21, 1935.

F. L. wooo SYRINGE Filed Feb. 5, 1932 INVENTOR, Frank L.Wood.

AOR

Patented May 21, 1935 s I I I H SYRINGE Frank n woba, Lynden, Wash. Application February 5,1932, Serial N6. 591,070

"1 Claim. 1 (01. 128-215) l My invention relates to improvements in throughout its entire length. The outer end of syringe springs, and has for an object to prothe plunger is providedwith flange H and when vide a metal spring suitable for being disposed the plunger fully occupies the cylinder its outer between the open end of the syringe cylinder and end protrudes from the same for a hand hold.

a boss on the outer end of the syringe plunger Said outer end of the plunger also is provided with 5 to'cushion the blows by the inner end of the boss I2 disposed adjacent cylinder flange 8 when plunger on the cylinder head during operative the inner end of the plunger is adjacent cylinder use of the syringe. I head 8. Adjacent the inner side of boss I2 is Syringe cylinders of the character with which groove l3 in the plunger. this invention is concerned are usually made of The syringe as thus described is suitablefor 10 glass and the closed or head'end thereof is easily operative use; but in practice, when not other- -broken out, by a blow from the plunger which wiseprotected, not infrequently the cylinder head may be caused to bear thereon during use there- 6 is broken from its body 4 by a blow from plunger of. I I0 delivered when ejecting liquid from the syringe 5 Hitherto various devices have been employed during operative use thereof. This destructive to avoid this danger, among which is a rubber blow occurs immediately following the passing band disposed around the outer end of the plungof the last portion of liquid from the cylinder er beneath a boss thereon to bear on the open into nozzle 6a. end of the cylinder and cushion the blow on the My invention is designed to cushion this blow UNITEDJSTATES PATENT OFFICE 2 head thereof which may be delivered by the inand thus save the cylinder from destruction ner end of the plunger. This has been found thereby.

objectionable in that rubber is injured during My spring, which is used to cushion said blow,

sterilization in boiling water. consists of spring clip l4 adapted for firmly clasp- Also, resilient clamping devices have been ening the cylinder to mount my cushioning spring gaged with the syringe plunger, to retardthe thereon. This clip is operatively disposed on the 25 free movement thereof during its entire travel. cylinder adjacent flange 8 and is sufliciently re- These required added power and sometimes ensilient to be easily removed and replaced in operacourage an excessive use thereof thus increastive position. Fastened to clip 14, preferably ining the force of the blows on the cylinder head tegral therewith, is spring shank l8 shaped for rather than diminishing the same. passing over flange 8 at one of the flats 9 thereof,

Other objects of my improvement will appear and disposed adjacent the outer edge offlange 8 as the description proceeds. at [8w of the shank.

I attain these and other objects of my im- Shank I6 is bifurcated by a relatively large provement with the device illustrated in the acnotch providing tongues I1, H which are shaped companying sheet of drawings, which form a for disposal on opposite sides of plunger l0 ad- 35 part of this specification, in which Figure 1 is jacent thereto without, contacting. therewith. a side elevation of a glass syringe on which my When the several parts of the device are in the metal spring is mounted in operative position operative position shown in solid lines in Fig. 1 drawn on a larger scale than ordinarily used, annular boss l2 on the plunger bears on spring Fig. 2 is a top plan view of Fig. 1 with the syringe tongues l1, I! which react between the cylinder 40 plunger removed therefrom, and Fig. 3 is a perand said boss to retain the plunger in its position spective view of my spring shown alone. of proximity to the bottom I of the cylinder. Similar characters refer to similar parts When pressure is applied, as by hand, tothe outer throughout. Certain parts are broken away to end of the plunger to move the same farther into show other parts hidden thereby. the cylinder, as to its dotted-line position at 10',

With more particular reference to the desigll, !2', spring [6, [1,11 may yield allowing said nated parts: A glass cylinder 4 has a bore 5 and movement of the plunger to occur and move a closed end or head 6. An outlet through the tongues l'l toward the cylinder to occupy positions head is provided by nozzle to. The inner end shown for one of them at H in Fig. I. With 5 of the cylinder bore is, preferably, flat and at sufficient pressure applied to plunger flange ll right angles with the bore as shown at I. On the inner end of the plunger may be caused to the open end of the cylinder is provided flange bear on the bottom or head 1 of the cylinder, and 8 which has diametrically opposite flats 9, 9. when said pressure is released spring I6, I], I1 Plunger I0 is usually of glass and is mounted will react and move the plunger to its relative in cylinder 4 for reciprocation to which it is fitted position shown in solid lines in Fig. 1. 55

The outer end of lug I5 is preferably disposed adjacent the outer side of flange 8 of the cylinder but it may never contact with boss I2 of the plunger. This lug is shaped to closely fit flange 8 at one of flats 9 thereof and serves to localize clip M on the cylinder and also provide a finger hold useful when the spring assembly is being removed from or placed in its operative position.

In operation: The plunger is withdrawn to the position in the cylinder which admits therein the desired quantity of liquid and then is pushed into the cylinder, in the usual way, to expel the liquid through nozzle 6a and into and through the hypodermic needle, usually attached thereto but not shown, The syringe Will operate in all ways the same as though my springwerenotmountedthereon till, in its approach to the cylinder, plunger boss 52 bears on spring tongues I? when resilient opposition is ofiered thereby Warning the operator of the syringe that the charge of liquid therein is nearly expelled and further progress of the plunger will continue with caution till the head of the cylinder is reached by the plunger with a pressure which the same is well able to withstand without injury thereto.

1 If preferred, one of spring tongues I! will serve very well and the other may be omitted Also, in place of the fiat spring illustrated, a spring wire can be shaped to serve the purpose of the syringe spring.

Since my syringe spring is entirely made of metal, it mayremain in place on the syringe while the same is being sterilized by boiling water without injury to the spring. Also, its removal and replacement are so easily attained that the syringe may be freed from it whenever desired.

Having thus disclosed my invention, what I claim as new therein and desire to secure by Letters Patent is,-

A syringe comprising a barrel having a nozzle end and a plunger end, a ledge projecting out- Wardly from the plunger end, a plunger having an annular boss at the outer portion thereof and means for supporting and maintaining the inner end of the plunger out of contact with the nozzle end of the barrel in the normal lowermost position of the plunger in the barrel when the barrel is empty, said means comprising a clip of resilient material having a barrel embracing portion seated beneath the ledge, an integral resilient extension engaging the upper portion of the ledge and comprising a resilient finger extending upwardly from the ledge and having a terminal cam face, the length of the plunger from its fluidejecting end to the under side of the boss being less than that of the inner extent of the barrel plus the height of the terminal cam face of the finger above the upper edge of the ledge whereby a surface of said cam face will be engaged by the boss on the plunger at the moment when the plunger is in a position close to but still out of contact with the inner face of the nozzle end of the barrel, said boss thereupon, on application of further pressure applied to the plunger, flexing the finger and thereby enabling the plunger to be moved to a position where it makes contact with the inner face of the nozzle-end of the barrel. FRANK L. WOOD. 

